04
Vokera
Ignition Lockout / Repeated Failed Starts
Boiler displays 04 and locks out, no heating or hot water
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Incorrect gas pressure, Partially blocked burner, Faulty ignition transformer on PCB, Incorrect electrode gap
How to Fix / Troubleshooting
Safety first: Turn off power and gas. Only Gas Safe engineers should adjust gas valves or burner settings.
- Reset attempts: Try a single reset as per the user manual. If the boiler repeatedly locks out with 04, do not keep resetting.
- Check gas supply: Confirm other gas appliances work. If they do not, contact your gas supplier.
- Engineer tasks:
- Check inlet and burner gas pressures against Vokera data plate.
- Inspect burner for debris, rust flakes, or soot; clean or replace as necessary.
- Check ignition electrode gap and position.
- Test ignition transformer output from the PCB.
Persistent 04 faults require professional combustion analysis and gas valve checks.
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Repair Difficulty
Professional Required
5/5
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